Indicator switch



Ratented Jan. 20, 1931 UNITED STATES PATENT OFFICE 'rnons man; or mmerou, NEVADA, assrenoa or orm-nm T JOHN a. 3088,

' 01 nmnorou, NEVADA nmrca'ron swrr'cn Application med April 17,1920. serial-Ito. $55,905.

This invention relates to a thermostatic alarm and more particularly to a device by means 9f. which a circuit may be closed and a signal sounded when temperature varies and becomes either too hot or too cold.

It often happens that blossoms in a fruit orchard will be killed by frost or plants in a hothou'se damaged by the hothouse becoming either too hot or too cool. This loss could be averted if the owner orthe managerwere warned in time to set out smoke boxes in an orchard or regulate the heating system of a hothouse. 7

Therefore, one objectof the invention is to 5 provide an alarm including a bell or uivalent signal energized by electricity an an improved thermostatic switch by means of which the circuit may be closed when the temperature is a proaching the danger point.

Another 0 ect of the invention is to provide a circuit closer including ahand. which 4 moves according to variations in the temperature and settin hands insulated from the temperature-indicating hand and add. ted to be engaged by. the temperature-indicating hand so that when the temperature-indicating hand contacts with the setting hand the circuit will be closed and the alarm sounded.

Another object of the invention is-to allow the setting hands to be moved relative to a scale upon the dial of the thermometer and thereby allow the signal to be sounded at any temperature desired.

The invention is illustrated in the accompanying drawing, wherein Figure 1 is a new looking at the front face of the improved thermostatic circuit closer which controls sounding of the alarm,

Fig.2 is a sectional view throu h the circuit closer takenon the line 2'-2 of ig. 1 and including an electric bell and a circuit for the bell operatively connected with the "circuit closer, and r Fig.3 is an enlarged fragmentary sectional view taken on the line 33 .of Fig. 1. I

The signal with which the improved circuit closer constituting the subject-matter of this 7 invention is used includes a hell 1 which may be mounted in a house or at any other place where it can be easily heard by the owner or manager of an orchard or greenhouse. Wires 2 and 3 lead from the bell. The wire 2 is connected with one side of a battery or other source of electric energy 4 while from the other side of the battery extends a wire 5' having a switch 6 intermediate its length so that the circuit may be manually opened and closed when found necessary. The wires 3 and 5 are of sufiicient length to extend to the place where the thermostatic circuit closer is to be located and this circuit closer may be mounted upon a suitable support in an orchard or greenhouse.

This circuit closer is in some respects similar to a thermostat of a conventional construction and includes a casin 7 open at its front and inorder to close t e open front of the casing there has been provided a transparent closer-sheet 8 formed preferably of glass and retained in place by a rim 9 removably secured about the casing by screws or equivalent fasteners 10. A dial 11 is mounted in the casing intermediate the depth thereof and to this dial, which is formed of conductive material, the wire 5 is grounded, as shown at 12. A shaft 13 formed of conductive material passesthrough the dial, and in order to insulate the shaft from the dial, there has been provided a bushing 14, the forward end of which is threaded in order to receive a securing nut 15. The bushing 14 has an enlarged rear end portion 16 to limit its movement'outwardly throughfthe, dial and from this enlarged inner or rearjend portion of the bushing extends an arm 17 which is rigidly secured to the dial by a rivet or equivalent fastener 18. The upper portion 19 of the arm projects'rearwardly from the dial and to this portion is secured the outer end of'a thermostatic spring which is coiled about the shaft and has its inner end secured to the shaft. It will thus be. seen that when the spring is effected by change in temperature the shaft will be rotated and the tem rature-indicatin hand 21 which is secured rmly upon the 'orward end of the shaft by a securing nut 22 will be swung relative to a scale 23 marked or otherwise provided upon theouter face of the dial. The wire 3 is secured to the rear end of the shaft by a 100 v ers are formed of conductive material and the washer 28 bears against the dial, an electric connection will'be established between the dial and the setting hands but the two settinghands will bein insulated relation to the temperature-indicating hand. These two hands extend at opposite sides of the temperature-indicating hand and each of them carries a tongue or abutment, indicated respectively by the numerals-30 and 31, which project outwardly and the temperature-indicating hand carries a tongue 32 which projects inwardly. By this arrangement the two contacts 30 and 31 will be disposed in the path of movement of the contact 32 and may be engaged thereby in order to establish an electrical connection between the temperatureindicating hand and either of the setting hands and cause the circuit to be closed and the alarm bell to ring. 1

When the signal is in use, the bell is mounted where it can be easily heard and the thermostatic circuit closer mounted in an orchard or greenhouse to be protected. The hand 26 will be set a few degrees above freezing if the device is used to protect an orchard. If the circuit closer is located in a greenhouse, the hand 26 will be set at the lowest-point upon the scale which is considered safe and the hand 27 set a few degrees below thehighest point which it is considered safe. The

temperature-indicating hand moves in the usual manner as the spring 20 is affected by changes in temperature and when-it is substantially parallel to one of the setting hands its contact 32 will engage the contact of the setting hand and thereby close the circuit and cause the signal bell to ring. This will warn the owner or attendant of the orchard or greenhouse and as the signal is sounded while the temperature is still a few degrees away from the danger point there will beample time to take precautionary measures by setting Gut smoke boxes in an orchard or adjusting the heating system of a greenhouse.

Having thus described the invention, I claim: i "i Q d l. A thermostatic circuit closer comprising a casing open at its front, a dial of conductive -material in said casing having a scale upon its outer face, a shaft of conductive material extending through said dial, an insulating the rear portion of said shaft with its inner end anchored to the shaft and its outer end anchored to said arm and serving to rotate the shaft as itexpands and contracts, a setting hand of conductive material rotatable about said bushing-in front of the dial for adjustment relative to the scale and having conductive connection with the dial, a hand fast upon the front end of said shaft and adapted to make contact with the setting hand at a temperature determined by adjusting the setting hand, and conductors anchored to the shaft and dial.

2. A thermostatic circuit closer comprising a casing open at its front, a dial of conductive material in said casing having a scale upon its outer face, a shaftof, conductive material extending through said .dial, an insulatingbushing fitting about said shaft and having an arm behind the dial, a spring coiled about the rear portion of said shaft with its inner end anchored to the shaft and its outer end anchored to said arm and serving'to rotate the shaft as it expands and contracts, a temperature-indicating hand fast upon the front end of said shaft formed of conductive material and extending towards the scale, a setting hand of conductive material fitting upon said bushing between the dial and first hand and adapted to be swung to a set position relative to the scale, contacts extending from said hands and adapted to make contact to close a circuit when the first hand has been moved substantially into alignment with the setting hand, and conductors anchored to the shaft and dial.

'3. A thermostatic circuit closer comprising a casing open at its front, a dial of conductive material in said casing having a scale upon its outer face, a shaft of conductive material extending through said dial, an insulating bushing fitting about said shaft and having an arm behind the dial, a spring coiled about the rear portion of said shaft terial fitting upon said bushin between the dial and first hand and adapte to be swung to a set position relative to the scale, washers of conductive material upon said bushing in front of and in back of the setting ha'nd'with the rear washer bearing against said dial, a securing nut threaded upon said bushing and when tightened causing the setting hand tobe gripped between the washers and fries tionally held in a set position, abutments extending. from said ha'nds and adapted to contact and close a circuit when the first hand nsane moves substantially into alignment with the setting hand, and conductors anchored to the shaft and dial.

4. A thermostatic circuit'closer comprising a casing, a dial in said casing having a scale upon its outer face, a rotatable shaft extend-- ing through the dial and insulated therefrom,

a control spring coiled about said shaft with hand. being adapted to -contact with the setting hand and close a circuit when substantially in alignment therewith, and conductors having electric connection with the shaft and setting hand. I I

In testimony whereof I afiix my signature.

THOMAS HEAP. [1,. 8. a 

